Software defined networking (SDN) is an innovative network architecture, separates a control plane of a network from an actual structure of a physical topology, and provides a programmable interface for the control plane, where hardware devices in the physical topology do not control routing of packets anymore by using respective software, but receive forwarding rules from the control plane, and forward the packets according to these rules. In this way, in a network of a range (or referred to as an SDN domain), a centralized and unified control logic unit performs management on the network in the range, so as to resolve a management problem of a large quantity of disperse forwarding devices independently running in the network, so that design, deployment, operation and maintenance, and management of the network are completed by a control point, and differentiation of an underlying network is eliminated. The centralized and unified control logic unit may be an SDN controller, that is, the SDN controller provides a control plane, to perform unified control and management on devices in the SDN domain administrated by the SDN controller.
For devices administrated by the SDN controller, the SDN controller needs to send control commands to the devices to control forwarding rules of the devices, so that a data packet, forwarded according to a forwarding rule indicated by the SDN controller, of a specified service is transmitted on a service path constituted by the devices, but a fault may occur in an entire path or apart of the service path. When a fault occurs in the service path, to ensure normal transmission of the data packet of the specified service, generally a manner of pre-allocating resources is used to preset a protection path for the entire path of the service path or a part, in which a fault easily occurs, of the service path. However, in the SDN technology, how the SDN controller continues to perform data transmission for the specified service by using the protection path corresponding to the service path when a fault occurs in the service path, to protect the faulty service path is a problem urgently to be resolved in the prior art.